The present invention relates to font disks for phototypesetters and, more particularly, to an improved font disk having indicia or characters and a strobe timing track that contains both timing marks for the indicia and digitally encoded data for the particular font disk.
Phototypesetters and optically readable font disks therefor are well known in the art. Representative examples of commercially available phototypesetters include Mergenthaler (Linstron Model 202) and AM International Model 4800. The patent literature describes a variety of phototypesetters and their associated optically readable font disks. See for example U.S. Pat. Nos. 2,787,199 and 3,896,454 for phototypesetting apparatus and 2,888,865, 3,821,770, 3,972,054 and 4,119,977 for examples of optically readable font disks for phototypesetters.
In addition to describing a phototypesetting apparatus, U.S. Pat. No. 3,896,454 also illustrates a font disk having alphabetic characters or other indicia arranged in concentric circles on the disk. Each character is identified by a number expressed in binary code. The binary code character information is carried in a ring on the disk with the binary number for each character being located 180 degrees from its associated character. In addition to the binary coded character information, the disk also carries four rings of marks which are associated with the characters located 180 degrees from the respective marks and which indicate the width of the respective characters. A pulse mark is provided for each character on the disk with the leading edge of the pulse mark determining the firing of the strobe light for the typesetter.
Although U.S. Pat. No. 3,896,454 depicts binary coded character information on a font disk, the character information is independent of and physically removed from the timing pulses of the strobe track. This configuration is wasteful of disk area and limits the number of font tracks that can be placed on a given font disk.
It is accordingly, a general object of the invention to provide an improved font disk for a phototypesetter.
It is a specific object of the invention to provide a phototypesetter font disk in which font information or other data is integrated with and contained within the timing or strobe track of the font disk.
It is another object of the invention to provide digitally encoded data pulses in the font disk strobe track between timing strobe marks for the font characters.
It is still another object of the present invention to provide a phototypesetter font disk in which character validation data is encoded within and forms a part of the timing strobe track.
It is a further object of the invention to provide a font disk having font identification data encoded within the timing strobe track of the font disk.
It is a feature of the invention that other font information such as, character width values, Kerning values and other character attributes can be digitally encoded in the timing strobe track of the font disk.